Robert W. Freckmann and Michel G. Lelong

Plants annual or perennial; their habit variable. Culms 2-300 cm, herbaceous, sometimes hard and almost woody, or woody, simple or branched, bases not cormlike; internodes solid, spongy, or hollow. Leaves cauline, basal, or both, basal leaves not forming a winter rosette; ligules membranous, usually ciliate; blades filiform to ovate, flat to involute, glabrous or pubescent, cross sections with Kranz anatomy and 1 or 2 bundle sheaths or with non-Kranz anatomy; photosynthesis C₄with NAD-me or NADP-me pathways, or, in plants with non-Krantz anatomy, C₃. Inflorescences terminal on the culms and branches, often also axillary, terminal panicles typically appearing after midsummer; sterile branches and bristles absent; disarticulation usually below the glumes, sometimes at the base of the upper florets, if at the base of the upper florets, then the florets not very plump at maturity. Spikelets 1-8 mm, usually dorsally compressed, sometimes subterete or laterally compressed, unawned. Glumes usually unequal, herbaceous, glabrous or pubescent, rarely tuberculate or glandular, apices not or only slightly gaping at maturity; lower glumes minute to almost equaling the spikelets, 1-9-veined, truncate, acute, or acuminate; upper glumes slightly shorter to much longer than the spikelets, 3-13(15)-veined, bases rarely slightly sulcate, apices rounded to attenuate; lower florets sterile or staminate; lower lemmas similar to the upper glumes; lower paleasabsent, or shorter than the lower lemmas and hyaline; upper florets bisexual, 2/3 as long as to equaling or exceeding the upper glume, sessile or stipitate, apices acute, puberulent, or with a tuft of hairs; upper lemmas usually more or less rigid and chartaceous-indurate, usually shiny, glabrous, and smooth, sometimes pubescent, sometimes verrucose or faintly transversely rugose, margins involute, usually clasping the paleas, rarely with basal wings or lunate scars, apices obtuse, acute, apiculate, or with small green crests; upper paleas striate, rarely transversely rugose; lodicules 2; anthersusually 3. Caryopses smooth; pericarp thin; endosperm hard, without lipid, starch grains simple or compound, or both; hila round or oval. x = 9 (usually), sometimes 10, with polyploid and dysploid derivatives. Name from the Latin panis, bread, or panus, an ear of millet.

Panicum is a large genus, but just how large is difficult to estimate because its limits are not yet clear. The treatment presented here differs from that in FNA 25 in the transfer of P. obtusum to Hopia obtusa (Zuloaga et al. 2007), of P. gymnocarpum to Phanopyrum gymnocarpum (Aliscioni et al. 2003; Zuloaga et al. 2007), and of P. bulbosum and P. plenum to Zuloagaea bulbosa (Bess et al. 2006). The articles cited provide the justification for the changes.

Most species of Panicum are tropical, but many grow in warm, temperate regions. Of the thirty species occurring in the Flora region, twenty-one are native, seven are established introductions, and two are not established within the region. Within the Flora region, Panicum is most abundant in the southeastern United States. Many species grow in early seral stages or weedy areas; some grow at forest edges, in prairies, savannahs, deserts, forests, beaches, and in shallow water.

Panicum miliaceum has been grown since prehistory in China and India as a cereal grain, and is a common component of bird seed. Seeds of P. hirticaule subsp. sonorum have been used for food by the Cocopa tribe of the southwest. Important hay and range species include P. virgatum, P. rigidulum, and P. repens.

Apomixis, polyploidy, and autogamy have produced numerous microspecies in some groups; hybridization and introgression has resulted in a reticulum of intergrading forms in some complexes. The number of taxa recognized has varied widely over the past century.

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SELECTED REFERENCES Aliscioni, S.S., L.M. Giussani, F.O. Zuloaga, and E.A. Kellogg. 2003. A molecular phylogeny of Panicum (Poaceae: Paniceae): Tests of monophylly and phylogenetic placement within the Panicoideae. Amer. J. Bot. 90:796-821; Bess, E.C., A.N. Doust, G. Davidse, and E.A. Kellogg. 2006. Zuloagaea, a new genus of neotropical grass within the "Bristle Clade" (Poaceae: Paniceae). Syst. Bot. 31:656-670; Darbyshire, S.J. and J. Cayouette. 1995. Identification of the species in the Panicum capillare complex (Poaceae) from eastern Canada and adjacent New York State. Canad. J. Bot. 73:333-348; Giussani, L.M., J.H. Cota-Sánchez,F.O. Zuloaga, and E.A. Kellogg. 2001. A molecular phylogeny of the grass subfamily Panicoideae (Poaceae) shows multiple origins of C₄ photosynthesis. Amer. J. Bot. 88:1993-2001; Hitchcock, A.S. 1951 [title page 1950]. Manual of the Grasses of the United States, ed. 2, rev. A. Chase. U.S.D.A. Miscellaneous Publication No. 200. U.S. Government Printing Office, Washington, D.C., U.S.A. 1051 pp.; Hitchcock, A.S. and A. Chase. 1910. The North American species of Panicum. Contr. U.S. Natl. Herb. 15:1-396; Reed, C.F. 1964. A flora of the chrome and manganese ore piles at Canton, in the Port of Baltimore, Maryland and at Newport News, Virginia, with descriptions of genera and species new to the flora of the eastern United States. Phytologia 10:321-405; Zuloaga, F.O. 1987. Systematics of New World Species of Panicum (Poaceae: Paniceae). Pp. 287-306 in T.R. Soderstrom, K.W. Hilu, C.S. Campbell, and M.E. Barkworth (eds.). Grass Systematics and Evolution. Smithsonian Institution Press, Washington, D.C., U.S.A. 473 pp.; Zuloaga, F.O., L.M. Giussani, and O. Morrone. 2007. Hopia, a new monotypic genus segregated from Panicum (Poaceae). Taxon 56:145-156; Zuloaga, F.O. and O. Morrone. 1996. Revisión de las especies Americanas de Panicum subgenera Panicum sección Panicum (Poaceae: Panicoideae: Paniceae). Ann. Missouri Bot. Gard. 83:200-280.

T.A. Cope (1995) Panicum. Flora of Somalia 4:

Plants annual or perennial. Leaves: blades flat or inroled, linear to ovate. Inflorescences panicles, usually highly branched, occasionally contracted about the primary branches. Spikelets dorsally or weakly laterally compressed, ovate to oblong; glumes hyaline to membranous, usually the lower shorter than and the upper equallling the florets; lower florets male or sterile, the lemmas usually resembling the upper glumes, with or without paleas; upper lemmas about as long as the spikelets, crustaceous, smooth or granular, the margins enrolled and clasping the edges of the pales. Caryopses ellipsoid, dorsally compressed. 

Panicum is a genus of about 265 species. They grow throughout the tropics with some extending into temperate regions of North America. 

Key to the species of Panicum in Somaliand and Somalia.

.Global distribution of Panicum.

Note: GBIF records include introduced and cultivated plants. Consequently, the distribution shown often differs from statements about a taxon's native distribution.

Aliscioni, S.S., L.M. Giussani, F.O. Zuloaga, and E.A. Kellogg. 2003. A molecular phylogeny of Panicum (Poaceae: Paniceae): Tests of monophylly and phylogenetic placement within the Panicoideae. Amer. J. Bot. 90:796-821.

Bess, E.C., A.N. Doust, G. Davidse, and E.A. Kellogg. 2006. Zuloagaea, a new genus of neotropical grass within the "Bristle Clade" (Poaceae: Paniceae). Syst. Bot. 31:656-670; 

Darbyshire, S.J. and J. Cayouette. 1995. Identification of the species in the Panicum capillare complex (Poaceae) from eastern Canada and adjacent New York State. Canad. J. Bot. 73:333-348.

Giussani, L.M., J.H. Cota-Sánchez,F.O. Zuloaga, and E.A. Kellogg. 2001. A molecular phylogeny of the grass subfamily Panicoideae (Poaceae) shows multiple origins of C4 photosynthesis. Amer. J. Bot. 88:1993-200.

Hitchcock, A.S. 1951 [title page 1950]. Manual of the Grasses of the United States, ed. 2, rev. A. Chase. U.S.D.A. Miscellaneous Publication No. 200. U.S. Government Printing Office, Washington, D.C., U.S.A. 1051 pp.

Hitchcock, A.S. and A. Chase. 1910. The North American species of Panicum. Contr. U.S. Natl. Herb. 15:1-396.

Reed, C.F. 1964. A flora of the chrome and manganese ore piles at Canton, in the Port of Baltimore, Maryland and at Newport News, Virginia, with descriptions of genera and species new to the flora of the eastern United States. Phytologia 10:321-405.

Zuloaga, F.O. 1987. Systematics of New World Species of Panicum (Poaceae: Paniceae). Pp. 287-306 in T.R. Soderstrom, K.W. Hilu, C.S. Campbell, and M.E. Barkworth (eds.). Grass Systematics and Evolution. Smithsonian Institution Press, Washington, D.C., U.S.A. 473 pp.

Zuloaga, F.O., L.M. Giussani, and O. Morrone. 2007. Hopia, a new monotypic genus segregated from Panicum (Poaceae). Taxon 56:145-156.

Zuloaga, F.O. and O. Morrone. 1996. Revisión de las especies Americanas de Panicum subgenera Panicum sección Panicum (Poaceae: Panicoideae: Paniceae). Ann. Missouri Bot. Gard. 83:200-280.